Added browsertest to assert that extension API calls are counted as V8RecursionScopes and delay mic…

chrome/test/data/extensions/api_test/mutation_observers/background.js

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+window.addEventListener('DOMContentLoaded', function() {
+  var body = document.body;
+  var div = body.appendChild(document.createElement('div'));
+  var input1 = body.appendChild(document.createElement('input'));
+  var input2 = body.appendChild(document.createElement('input'));
+
+  input1.focus();
+  input1.addEventListener('blur', function() {
+    div.setAttribute('baz', 'bat');
+  });
+
+  var success = false;
+  var mutationsDelivered = false;
+
+  var MutationObserver = MutationObserver || WebKitMutationObserver;
+  var observer = new MutationObserver(function() {
+    mutationsDelivered = true;
+    if (success)
+      chrome.test.succeed();
+  });
+  observer.observe(document, { subtree: true, attributes: true });
+
+  // The getAll callback should be counted as a V8RecursionScope and cause
+  // the delivery of MutationRecords to be delayed until it has exited.
+  chrome.windows.getAll(function() {
+    div.setAttribute('foo', 'bar');
+    input2.focus();
+    if (mutationsDelivered)
+      chrome.test.fail();
+    else
+      success = true;
+  });
+});